Reyal Jardine-Douglas, Sylvia Klibingaitis and Michael Eligon were gunned down by Toronto police in separate but similar incidents in the last three years.
The coroner's inquest — which is expected to raise questions about police use of force and how front-line officers deal with the mentally ill — heard from a police expert who repeatedly said officers have to react rapidly to evolving situations.
"Someone's condition isn't what drives the response. It's that behaviour that we have to respond to," John Weiler, the use-of-force co-ordinator at the Ontario Police College, explained.
"Once there's an imminent threat, all we do is respond."
Weiler spent the better part of three hours detailing police use-of-force training, focusing in particular on the model that officers use as a basis for making their decisions in the field.
"The model is dealing with behaviours. Not reasons for behaviours," he noted when asked why the model didn't have a category on how to deal with the mentally ill.
"We can't list everything in the model (like impaired driving and domestic violence). The model speaks to all those things now although they're not laid out in point form."
When asked by lawyers for the families of those killed if integrating specific information on how to better respond to mentally ill people would be beneficial, Weiler said such an addition could cause confusion.
But when presiding coroner David Eden asked if a different approach to the mentally ill would be adopted if scientific evidence showed it reduced the chance of death, Weiler said such an approach would be "fabulous."
Weiler emphasized that "de-escalation is always a consideration." If a situation has progressed beyond a certain point though, he said officers under threat are trained to use their firearms to protect themselves and others.
"We don't train officers to shoot to kill," he noted. "We train them to shoot to stop."
This week's proceedings are hearing primarily from policing and mental health experts in order to give the presiding jury a thorough grounding in current practices.
Before they heard Weiler's testimony, the jury was asked to keep an open mind through the proceedings.
Coroner's counsel Michael Blain said the five-member panel should remember that mental illness "is not the person,'' and police officers should not be defined by their actions.
Relatives of all three people who were shot by police were present for the start of the inquest, listening on with grim expressions as Blain outlined the circumstances of each death for the jury.
Michael Eligon was 29 when he died in February of 2012 after fleeing from a Toronto hospital dressed in a hospital gown and armed with two pairs of scissors.
Twenty-five-year-old Reyal Jardine-Douglas died in August of 2010 after pulling a knife out of his bag and advancing on an officer on a public transit bus.
And 52-year-old Sylvia Klibingaitis called 911 herself in October of 2011 — saying she was going to commit a crime — before she confronted officers with a knife in her hand.
All were thought to be experiencing mental health issues when they approached officers with sharp objects.
The province's police watchdog later cleared authorities of wrongdoing in all three cases, prompting calls for justice from the families of those killed.
Lawyer Peter Brauti, who is representing one of the officers involved in the cases, said he believes all evidence brought forward to date has shown police acted appropriately.
"The question is, do we give them different tools? For example, do we make sure they are all armed with Tasers? Do we give them training that will help deal with these situations better?" asked Brauti outside the coroner's court.
"Officers deal with situations all the time that require them to draw their weapons and tragedies are going to happen. This won't be a complete answer but let's try and move in that direction and improve things."
But John Weingust, a lawyer representing Jardine-Douglas's family at the inquest, said his clients believe their son's death was a "wrongful shooting."
"These weren't criminals, these were people suffering from emotional problems at the particular time...and all they had was either scissors or a knife," he said outside court.
"It seems to me that in regard to emotionally disturbed people, a different procedure has to be adopted."
Peter Rosenthal, who is representing Eligon's family, said he was "cautiously optimistic" the inquest would change how police forces respond to officers who fire at mentally ill people in similar situations.
"My hope is that this inquest really underlines the fact that police officers should try de-escalation way before they use weapons," he said.
"I hope the jury at the end of the day will insist that they do that by indicating that officers who fail to do that, in circumstances where it's appropriate, should be subject to discipline."
The inquest is expected to last eight weeks and will hear from more than 50 witnesses. The jury may make recommendations at preventing similar deaths but is not tasked with finding fault or laying any blame.